Hitherto, as a method for producing iodine heptafluoride (IF7), there has been known a method for obtaining iodine heptafluoride by blowing fluorine (F2) gas into a liquid of heated iodine pentafluoride (IF5) and by making iodine pentafluoride accompanied by fluorine gas pass through a reaction zone of 280-290° C. (Non-patent Publication 1). Furthermore, there has been proposed a method in which iodine pentafluoride or iodine (I2) is vaporized and mixed in a fluorine gas stream by using a vaporizer installed prior to a reactor, and then the mixed gas is introduced into the reactor heated to a temperature at which both of them react, thereby converting it into iodine heptafluoride (Patent Publication 1). It is described in Patent Publication 1 that the reaction cannot be continued by red heat at around the introducing port in the case of putting the raw material and fluorine directly into the reactor with no use of the vaporizer. On the other hand, as a method for producing iodine pentafluoride, there is proposed a method for producing iodine pentafluoride, in which solid iodine is dispersed in a iodine pentafluoride liquid previously produced, and then fluorine gas is blown with cooling at 20-30° C. (Patent Publication 2). As mentioned above, according to conventional iodine heptafluoride production methods, it is necessary to have a two-step reaction in which iodine pentafluoride is previously synthesized from iodine and fluorine, and then this is reacted with fluorine, or a complicated operation in which iodine pentafluoride or iodine is vaporized and mixed in a fluorine gas stream, and then the mixed gas is introduced into a reactor, thereby converting it into iodine heptafluoride.
Patent Publication 1: Japanese Patent Application Examined Publication No. 2-39443 B2
Patent Publication 2: German Patent No. 2035521
Non-patent Publication 1: Ind. Eng. Chem., 42, 1383 (1950)